http://www.church-on-the-net.com/ is said website, it has a weekly article (= sermon equivalent?), blogs, forums etc., but the standout is the Reference section, where I nearly got sidetracked by for several hours. It has a series of short articles about most of the major things - God, Jesus, prayer, suffering etc., and at the end of each has several web links to other helpful stuff on the topic, whether it's music videos, poems, clips from TV programmes, etc. So the section on Jesus links to bits of artwork, and the bit on 'church' directs you to a clip from the cartoon 'King of the Hill'. It really is very good.
http://www.rejesus.co.uk/expressions/index.html has been around for a few years, it's a good place to dig around, good quality stuff everywhere on the life and teaching of Jesus, and whilst you're looking you might stumble across an interesting meditation, bits of art, poetry, or a very well put together daily prayer.
The Church of England website has a small faith section at http://www.cofe.anglican.org/faith/ with some stories of people coming to faith, a brief definition of what a Christian is, but then signposts to the rejesus site above.
The Methodist church site has an exploring Christianity section, but again signposts rejesus. In fact, most of the main UK denominations send you to rejesus rather than having a major section on Christian life and faith on their own websites.
http://www.explorefaith.org/questions.html#faith is a site based on listing lots of questions that you might be asking yourself, then responding to the questions. The answers aren't cut and dried, which is a plus, and it's a very text-based site, which will be a plus to some and a minus to others.
A Google on Christianity throws up 'christianity.com', which I would have thought is a contradiction in terms. The '.com' means you get lots of adverts for stuff, which put me off reading anything they had to say.
Finally http://www.shipoffools.com/ , the granddaddy of decent Christian websites, doesn't set out to to answer any questions at all, but for anyone with a sense of humour who wants a more oblique approach to the Christian faith, it's a good place to start.
Meanwhile there is a discussion thread on the Cartoon Church website on whether evangelistic blogs actually work at all!
....and then after far too long foraging around the net, I couldn't find anything else worth linking to. What am I missing?